The headlines appeared this week like a recurring bad cold: “Your All-Electric Car May Not Be So Green,” “Your New EV May Actually Be Dirtier Than The Gas Powered Car It Replaced,” “Can Electric Vehicles Be 'Environmental Villains'?,” among others. 

A new study from the University of Minnesota assessed the cradle-to-grave “life cycle” impacts on air quality of conventional and alternative transportation. Its findings, which dovetail with information long known (but apparently not concise enough to fit into an attention-grabbing headline: Electric vehicles are really good for the environment, except when they’re recharged using coal-generated power. The Minnesota study presents a sobering stat: “coal-powered” EVs may actually increase environmental health impacts by 80 percent or more relative to using gasoline. As Green Car Reports puts it: “The study concludes that if an electric car is recharged with electricity generated by the coal-heaviest grids in the U.S., it causes almost twice as many deaths from air pollution as a comparable gasoline vehicle.”

That stings for residents of coal-heavy states like Illinois, Ohio, North Dakota, West Virginia, and Wyoming, who may want to drive as green as possible. The good news is that coal plants are being retired every month,  and as coal-dependent electricity grids clean up, so does the source of an electric car’s energy. There’s no way to clean up coal, but those coal states could eventually join the likes of California, New York, and states in New England and the Northwest,  where, the study concludes, “EVs powered by low-emitting electricity from natural gas, wind, water, or solar power reduce environmental health impacts by 50 percent or more” compared to gasoline. Recharge an EV using power generated from natural gas, and it produces only half the health impacts of a car running on conventional gasoline; turn to renewables -- either from a forward-thinking utility or panels on your roof – and electric cars produce only a quarter of the health-related problems of gasoline-powered cars. 

In related news, The Union of Concerned Scientists, whose comprehensive 2012 report State of Charge spells out where you’ll find the cleanest (and dirtiest) electricity grids in the country, recently noted that EVs themselves are becoming more efficient every year.